Multi-channel sound (MCS), such as stereo sound, surround sound, 3D sound, various polyphonic (e.g., octophonic) sound arrangements, ambiosonics, ambiophonics, etc., refers to any of various techniques for enriching sound reproduction quality of an audio source using multiple discrete audio channels routed to an array of loudspeakers operating in a coordinated fashion to encompass one or more listeners with differentiated sound signals from multiple directions. In the context of MCS systems, “echo” results from any condition by which a specific sound emitting from different loudspeakers travels different paths and reaches a listener at different times, thereby creating a duplicative, repeating, or “fuzzy” sound effect. For a multi-loudspeaker system, each loudspeaker can effectively contribute to echo effect because the sound produced by each loudspeaker will, to some extent, travel a unique acoustic path before reaching the ear of the listener.
To compensate for the echo effect, an MCS system may actively learn the acoustic paths from each of the loudspeakers with respect to a specific target listening location found within the acoustic environment. This active approach may comprise a calibration mode that produces one or more test sounds at each loudspeaker individually, measures these sounds using one or more microphones, and determines the learned acoustic path for each such loudspeaker with respect to the target listening location. However, a shortcoming of this approach is that the “calibration” performed by the MCS system is most applicable only to the specific characteristics of the acoustic environment at the time the calibration is performed, and thus works well for static (i.e., non-changing) acoustic environments. For acoustic environments with dynamic (i.e., changing) characteristics, the calibration may not be helpful and, in certain instances, may even contribute to (instead of diminish) echo effects.